[CodeHealth] Use Position::anchorNode instead of deprecatedNode.

Source/core/editing/InputMethodController.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 253 matching lines @@
     m_compositionNode = nullptr;
     m_customCompositionUnderlines.clear();
 
     if (!text.isEmpty()) {
         ASSERT(frame().document());
         TypingCommand::insertText(*frame().document(), text, TypingCommand::SelectInsertedText | TypingCommand::PreventSpellChecking, TypingCommand::TextCompositionUpdate);
 
         // Find out what node has the composition now.
         Position base = frame().selection().base().downstream();
         Position extent = frame().selection().extent();
-        Node* baseNode = base.deprecatedNode();
+        Node* baseNode = base.anchorNode();
         unsigned baseOffset = base.deprecatedEditingOffset();
-        Node* extentNode = extent.deprecatedNode();
+        Node* extentNode = extent.anchorNode();
         unsigned extentOffset = extent.deprecatedEditingOffset();
 
         if (baseNode && baseNode == extentNode && baseNode->isTextNode() && baseOffset + text.length() == extentOffset) {
             m_compositionNode = toText(baseNode);
             m_compositionStart = baseOffset;
             m_compositionEnd = extentOffset;
             m_customCompositionUnderlines = underlines;
             for (auto& underline : m_customCompositionUnderlines) {
                 underline.startOffset += baseOffset;
                 underline.endOffset += baseOffset;
@@ skipping 121 matching lines @@
     TypingCommand::deleteSelection(*frame().document());
 }
 
 DEFINE_TRACE(InputMethodController)
 {
     visitor->trace(m_frame);
     visitor->trace(m_compositionNode);
 }
 
 } // namespace blink